1. Field of the Invention
The present invention relates to an improved plasma CVD apparatus.
2. Description of the Prior Art
A plasma CVD apparatus can vapor-deposit an amorphous silicon film on a surface of an electrophotographic photoconductor drum.
FIG. 1 shows a schematic view of such a plasma CVD apparatus. In FIG. 1, A denotes a reactor, K denotes a cylindrical cathode electrode arranged in the reactor A, d denotes an anode electrode drum coaxially arranged in the cathode electrode K, and h denotes a heater arranged in the drum d. The drum d is rotated in a direction of an arrow by drive means, not shown. The cathode electrode K has a dual wall structure. A reaction gas supplied from a gas supply source (not shown) through a gas introduction port p is supplied into the dual wall structure and the reaction gas is discharged from a gas discharge port g formed in an inner wall of the dual wall structure toward the cathode electrode K. An RF power from a power supply (not shown) is supplied to the cathode electrode K. Thus, a plasma discharge is created between the cathode electrode K and the anode electrode drum d and an amorphous silicon film is formed on the surface of the drum d. The gas contributed to the reaction is taken out of a gas exhaust port q formed in the reactor A.
In such a plasma CVD apparatus having the coaxial cylindrical electrode structure, when a number of photoconductor drums are to be manufactured, a plurality of pairs of the cathode and anode electrode structures must be arranged in the reactor. However, since each pair of electrodes is of cylindrical electrode structure, much wasteful space is formed between the structures if a plurality of such structures are arranged. As a result, the number of drums accommodated per unit reactor area is lowered and a manufacturing efficiency is lowered.